You need to be running 6.2(2), and if you have LAN-based failover configured then yes, you don't need the failover cable. The documentation is correct. The failover unit will definately boot up without the cable plugged in, but if you're seeing something different, please connect a laptop to the console port of the standby and power it up and send us the output.
You CAN use a cross-over, but you shouldn't. If you use a crossover and the cable goes bad or the primary PIX shuts down, the interface on BOTH PIX's will go down, so the standby won't be able to detect that the primary has failed, it'll just think it's own interface has died. If you plug them into a switch, then if the primary goes down, the interface on the secondary is still up and the secondary can therefore detect that the primary has failed.
